Fusion Energy Sciences

Research sponsored by DOE's Office of Fusion Energy Sciences is steadily bringing the promise of this sustainable and environmentally benign energy source closer to fruition. The broad spectrum of fusion research at NERSC encompasses a variety of magnetic confinement configurations--tokamak, spheromak, and stellarator--as well as inertial confinement.

One of the current objectives of tokamak research is to develop ways to inject cold fuel into the core of the tokamak. Recent experiments indicate that if pellets of cold fuel are injected from the outside of the tokamak, they are expelled without reaching the center, while if the pellets are injected from the inside (i.e., the hole of the donut), the fuel does reach the center. This effect was reproduced this year in a 3D simulation code, which is helping physicists understand the phenomenon.

In other tokamak research, gyrokinetic turbulent transport simulations have been used to analyze and predict experimental results, and a new zero-transport state has been found. Researchers also developed and parallelized the first 3D global-turbulence simulation code in a realistic toroidal x-point geometry.

Simulations are helping physicists develop other fusion configurations as well, including new stellarator configurations that provide improved plasma confinement and stability within a more compact design. Plasma formation and magnetic reconnection in a spheromak were successfully simulated this year. And to help develop an inertial fusion driver, researchers are simulating heavy-ion induction acceleration to study basic beam physics, analyze beam behavior in experiments, and predict beam behavior in future facilities.

Contours of magnetic field strength on the last closed flux surface of an optimized stellarator configuration, demonstrating good toroidal symmetry.